1. Field of the Invention
The present invention relates, in general, to a system for monitoring multiple digital test points on a continuous dynamic basis and for acquiring signal values representative of, for example, performance, activity level, or other suitable operating parameter indicative of the operational status of each digital test point, all without imposition of any physical load on the digital test points or on the equipment with which such points are associated, and for displaying such dynamically acquired information after processing thereof on both a pseudo real time digital basis and on a digitally pictorial historic basis extending over a preselected period of time; and, more particularly, to a monitoring/display system of the foregoing character, and the display produced thereby, where any desired number n of discrete totally independent digital test points (where "n" is any whole integer) can be simultaneously monitored, the resulting n signal values processed, and any selected group of y of the monitored n signal values (where "y" is any whole integer ranging from "1" to on the order of "8") can be simultaneously displayed on a single living display (or on each of multiple living displays) as y independent discrete channels of information each displaying a pseudo real time digital portrayal of the status of the operational parameter being monitored and an historical digital portrayal of the status of that parameter over the most recent period of time of interest, which may range up to 90 minutes or more.
By "living display", it is meant that the current information is displayed on a pseudo real time basis with the oldest historical displayed information being progressively scrolled off the visual display as new current information is displayed for the first time. By "pseudo real time", it is meant that in its broadest aspects the invention permits averaging of successive signal values measured over a given time period and display of the averaged value as contrasted with the instantaneous value.
For example, the present invention is hereafter described in connection with an exemplary monitoring system for measuring the activity level of multiple digital test points wherein each test point is scanned over successive time intervals on the order of 5 seconds each, and with successive scans being averaged over a selected time interval such, for example, as 45 seconds, with the digital information actually displayed being respresentative of the average of the signal value over the preceding 45 second time interval (or other selected time interval). As the ensuring description proceeds, however, those skilled in the art will appreciate that the particular time intervals employed are a matter of choice and a function of the accuracy and resolution desired for the information being displayed. That is, while the invention is here described in connection with an exemplary system for continuously monitoring the activity level status for n digital test points and displaying y channels of the monitored information on a pseudo real time basis and an historical basis over the preceding 90 minute period, the system can be readily programmed or reprogrammed to either extend or shorten the historic time period and, concommitantly, to extend or shorten the incremental periods over which the monitored information is averaged.
2. Prior Art
As more and more highly sophisticated and expensive data processing systems, CPU's, computer controlled machine tools, and the like, have been developed, there has been an ever increasing demand for systems and procedures to insure that such capital intensive equipment is utilized to its fullest potential. The prior art is replete with numerous disclosures of efforts to monitor such sophisticated equipment for a wide range of reasons. Typical of such prior art approaches are those disclosed in, for example, U.S. Letters Pat. Nos. 3,399,298-Taylor, 3,522,597-Murphy, 3,540,003-Murphy, 3,585,599-Hitt et al, 3,599,091-Warner, Jr., 3,771,131-Ling, and 3,818,458-Deese.
In the Taylor patent, the patentee discloses a system for measuring the efficiency of a given data processor when operating with a given program so as to permit program revision where necessary to make better use of the data processor. A secondary computer serves to drive the display device.
Murphy, in his aforesaid U.S. Pat. No. 3,540,003, discloses a special purpose digital collection system for computer monitoring. The disclosure pertains particularly to the data collection process, employing associative memory techniques, comparators, and a computer for detailed analysis of the digitally collected data. In Murphy's U.S. Pat. No. 3,522,597, the patentee discloses the use of a cathode ray tube (CRT) display of analog information.
Hitt et al, disclose a digital hardware control system for monitoring digital test points in a CPU; while Warner discloses the use of isolation probes to sense digital signals in a computer system without imposing line loads and without degrading system performance. In the Ling patent, probes are permanently hardwired to the computer; and, time variable data is captured using timing signals from the computer being monitored.
Deese discloses methods and apparatus for monitoring the utility and performance of a general purpose computer without affecting operation of the computer by sensing changes in the operative state of the computer and capturing the contents of certain status registers and locations in memory and in response to such sensed changes.
Perhaps the most pertinent of the known patented prior art disclosures is that contained in U.S. Letters Pat. No. 3,588,837-Rash et al. This patent is specifically directed to a system for determining the activity level of multiple data paths and/or other signals. To accomplish this, the patentees accumulate signals in analog or digital form from the CPU of interest, process the signals to produce outputs indicative of the percent utilization of the CPU channel inputs, store the processed information first in a temporary memory and then in a main computer memory, and ultimately permit retrieval of stored information from the main computer memory and display thereof on a CRT screen. The system appears capable of displaying only one channel of information at a time rather than multiple channels; display requires operator intervention; and, the system appears to be incapable of simultaneously displaying: (i) multiple independent discrete channels of information on a single display; and/or (ii), information on both a real time or pseudo real time digital basis and on a digital historic basis.
Another known prior approach comprises an experimental system heretofore employed by the assignee of the present invention. In that experimental system, data representative of percent utilization of multiple CPU channels was displayed by means of a continuous strip chart recorder employing multiple pens for scribing multiple, generally parallel, vertical continuous traces on a scrolled paper sheet with the traces being indicative of the percent utilization of each CPU channel of interest. The information was not presented in digital format; but, rather, in map format. The physical paper trace was monitored by video cameras and replicated at remote video monitors.
In general all of the foregoing prior art approaches are characterized by their complexity and are relatively costly. The known patented systems are generally not intended to simultaneously display multiple discrete independent channels of information on a single visual display, nor is the display comprised of a real time or pseudo real time display coupled with a scrolled living historical display. In general, such systems do not permit of instantaneous recognition of trend data for multiple channels of interest, nor do they provide display with programmed annotations of interest.